Advertisements may be placed in public locations so that they may be viewed by those who pass by the advertisements. For example, advertisers may buy advertisement space on billboards or bus stop street furniture to build brand awareness. However, it may be difficult for advertisers to determine how large of an audience is actually able to view a particular advertisement over a period of time. Moreover, it may be difficult for the advertisers to gain information regarding the demographic or other attributes of the audience who may be able to view the advertisement.